使用json所要用到的jar包，包含以下文件：
json-lib-2.2.3-jdk15.jar
commons-beanutils-1.7.0.jar
commons-httpclient-3.1.jar
commons-lang-2.3.jar
commons-logging-1.1.1.jar
commons-collections-3.2.1.jar
ezmorph-1.0.3.jar

如果不关联这些包，则会出现以下错误：
java.lang.NoClassDefFoundError: net/sf/ezmorph/Morpher
java.lang.NoClassDefFoundError: org/apache/commons/collections/map/ListOrderedMap
java.lang.NoClassDefFoundError: org/apache/commons/beanutils/DynaBean
java.lang.NoClassDefFoundError: org/apache/commons/codec/DecoderException
java.lang.NoClassDefFoundError: org/apache/commons/lang/exception/NestableRuntimeException
java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory